LED light source used in the greenhouse fill light

　　At present, the commonly used artificial light sources of greenhouse mainly  fluorescent lamps, high pressure sodium, low pressure sodium, metal halide  lamps. In recent years, with the successful development of high-power LED, new  energy-saving LED light source has caused widespread concern.

　　Ordinary fluorescent lamps provide more green, about 50%, and the rest are  mostly red, blue, and each accounted for about 25% of the total spectrum, far  red spectral ratio is very low. Fluorescent high luminous efficiency, long life  (about 12000h), but less power (Currently, there are two kinds of commonly used,  28W and 36W), required to meet certain illumination lamps and more. Because it  contains a lot of green, likely to cause excessive growth of crops. Currently  used in plant tissue culture.

　　Sodium mercury and sodium vapor light source emitting gas is divided into two  kinds of low-pressure sodium lamps and high pressure sodium lamp. Appeared  earlier low pressure sodium, sodium vapor pressure of not more than a few Pa,  which focused on the yellow light emission spectrum 589nm, usually only with the  use of other sources. Luminous efficiency of up to 200lm / W, long life  (approximately 9000h). HPS standard working sodium vapor pressure of about  10kPa, the emission spectrum has more orange and less blue-green. High luminous  efficiency, high power, long life (about 12000h), currently used by more fill  light in the greenhouse. However, due to high pressure sodium light is hot, the  surface temperature is high, heat a large, not brachytherapy crops.

　　Metal halide lamps are mercury vapor and rare metal halide arc thus mixing a gas  discharge light-emitting source. May exhibit different spectral composition by  varying the metal halides. High luminous efficiency, high power, long life  (5000h ~ 20000h). But the filler within the mercury lamp, when the lamp is  damaged or fails to use abandoned when will pollute the environment. Spectrum  contains more far-red light, heat, not brachytherapy crops.

　　LED (light emitting diode) light source developed in recent years is a new  energy source. Compared with incandescent, fluorescent and high pressure sodium  lamps and other artificial light source, LED has significant advantages:

　　DC low voltage power supply. Low-power color LED forward voltage is typically  1.5V-2.8V, high-power LED forward voltage is typically 3V-4V, far less than the  safe voltage.

　　Energy saving. Sodium and metal halide lamp is a gas discharge lamps, by heating  up the metal vapor discharge light-emitting element. LED light source is solid,  does not require heating can emit light, is a cold light source, thus reducing  its power consumption in heating.

　　monochromatic light source, high luminous efficiency. LED may emit monochromatic  light of a half-wave wide mostly ± 20nm, can accurately provide the required  spectrum of plants, without wasting energy emits yellow light, green light and  other unwanted plants spectrum.

　　Small, flexible application. Can design a slim and light fixtures, use a large  space.

　　environmentally friendly. LED is a solid light source, no mercury and other  harmful substances, will not cause pollution in the installation, which waste  can be recycled. LED light source is environmentally friendly green light.

　　Long life. LED is a solid light source, there is no internal loose parts, no  glass, easy burning filament and other vulnerable parts, mechanical strength,  resistance to vibration, impact resistance, life expectancy of up to more than  50000h.

　　Obvious advantages of the LED light source has attracted attention of the  Netherlands, Japan, the United States and other countries of scholars,  especially in recent years successfully developed high-power LED for LED fill  light in the greenhouse application basis.